Various types of marking devices are known in the prior art. However, what has been needed is a finger-mounted marking apparatus including a finger ring having a ring-shaped finger member and a substantially trapezoidal continuous upper member. What has been further needed is a single substantially trapezoidal opening disposed within the substantially trapezoidal continuous upper member of the finger ring from a rear surface to a front surface. Lastly, what has been needed is a writing utensil slidably and removably engageable within the single substantially trapezoidal opening, with the ring-shaped finger member of the finger ring selectively slidable on a finger of a wearer. The finger-mounted marking apparatus thus allows a wearer to make a mark on a work surface simultaneously with the measurement itself, since the wearer can now utilize both of his hands to make the measurement and will no longer require the assistance of a second person.